Impact of the Low- to High-Density Lipoprotein Cholesterol Ratio on Composition of Angiographically Ambiguous Left Main Coronary Artery Plaque.

Background: A high low-density lipoprotein cholesterol (LDL-C) to a high-density lipoprotein cholesterol (HDL-C) ratio is associated with cardiac events, while the left main coronary artery (LMCA) is considered to be an important target of atherosclerotic plaque accumulation. This aim of the present study was to investigate the relationship between a LDL-C/HDL-C ratio and the characteristics of tissue components of LMCA plaque.Methods and Results: One-hundred-twenty consecutive patients with stable angina pectoris who received chronic statin treatment underwent percutaneous coronary intervention for the left coronary artery. We prospectively performed integrated backscatter (IB) intravascular ultrasound (NUS) to their LMCAs and evaluated the tissue characteristics. According to the median value of their LDL-C/HDL-C ratios (2.4), they were divided into 2 groups [high LDL-C/HDL-C ratio (>2.4) (n=60) or low LDL-C/HDL-C ratio (<= 2.4) (n=60)]. There was no significant difference in the data analyzed using conventional IVUS between the 2 groups. In the IB-IVUS analysis, patients with a high LDL-C/HDL-C ratio had a larger lipid volume and a smaller fibrous volume compared to patients with a low LDL-C/HDL-C ratio (52 +/- 10% vs. 48 +/- 10%, P=0.014 and 45 +/- 9% vs. 50 +/- 10%, P=0.010).Conclusions: A high LDL-C/HDL-C ratio was associated with a high percentage of lipid volume and a low percentage of fibrous volume in LMCA lesions. Our findings might well suggest the increased risk of cardiovascular events in patients with a high LDL-C/HDL-C ratio. (Circ J 2011; 75: 1960-1967)